Production of gas mixtures containing carbon monoxide and hydrogen



Aug. 19, 1952 w. K. LEWIS, R 2,607,670

PRODUCTION OF GAS MIXTURE CONTAINING CARBON MONOXIDE AND HYDROGEN Filed Aug. 15, 1947 NITROGEN OUTLET METAL OXIDE REGENERATOR 44 Q 36 A \REDUCED METAL OXIDE L a (FLUIDIZED) A 34 I O f 2 c T AIR INLET ilks A 40 INTER STAGE METAL OXIDE (FLUIDIZED) I GAS L'NE\ SECOND STAGE I GENERATOR sT l GENERATOR sTEAM INLET Inventor WARREN K. LEWIS,JR.

Attorney backs because it avoids the sintering and fiuidization troubles associated with the 'high temperatures required for complete conversion and yet does not involve the high expense of a large oxygenproducing plant, the amount of oxygen required for the final cleanup of hydrocarbons in the second stageijbeing relativelysmall; Fur- 'thermore, such metal oxide fines as escape from the first into the second'stage will sinter and agglomerate at the high temperature of the' latter; thus facilitating their separation from the product gas.

' sizes, superficial linear gas velocities of about 0.3-3 it. per second, preferably 1-2 ft. per second,

aresuitable for. proper fluidization.

The temperatures suitable for stage of the invention depend mainly on the reactivity and selectivity for CO formation, of the inetal oxide used in the first stage. Quite generally, it may be stated that satisfactoryresults nay be;

secured with the more reactive and selective metal oxides at first stage temperatures of about 1400-1600 F. to obtain about 65-90% conversion of hydrocarbon gases-to Couand H2.I f 'Ihesec'ond stage may be successfullyt operated at temperatures of about 2000 -2500? F4, prefer: ably about 2l00--'2300 F." to accomplish, substane tially complete conversion-of the remainingabout 10-35% 5 of the hydrocarbon :charge. About 8-12%-byvolume ofoxygen of95% purity, based on i the original hydrocarbon 7 charge is usually sufiicient for the clean-up stage of. the process. At theseconditions the equilibria of the reactions CH4+QO2 -*2Hz-F2CO Wilt-Shift,StIOIlglytO; the, right and. only small amounts of CO and 11-12 will be lost ,byoxidation to comma-H20. .The oxygen consumptionz l the second stage is minimized by the, fact that the partially converted gas is supplied atthe high temperatures of .the first stage, which; are con;

siderably higher than could be, efficiently obtained are capable of ;oxidizing gaseous hydrocarbons to CO and H2 at the conditions of the first process stage; since the process, involves ,reoxidation of reduced. metal oxide with air, the oxidesshould have such an jafiinityior'oxygen at the tempera: tures of the first stage that their oxygen partial pressures at; equilibrium with both higher and lower stages of oxidation present are less than bout-.040 atmospher and, re e bl es tha 0.01,. atmosphere sothat substantially all the oxygen of the airused for regeneration can be-bound bythelowe ta eot at e @WhHeeer i me oxid i h. are r du e til-meta such a e ou dde-cl rml O may lowf conversion teinperat ures maintained in theLfirststage of the process. The metal'oxides' may be supported on carrierssuch as kieselguhr,

alumina, silica gel, bento'nites, 'etc.; which in-Y,

crease the active surface or themetal oxid'sl "Having'set'forth the general nature and objects, the invention will be best understood from the .more .detailedldescription hereinafter in which-referenoewill be made to the accompany- -ing drawing-which is a semi-diagrammatic view of apparatus suitable to practice a preferred embodiment of the invention.

Referring now in detail to the drawing, the system illustrated therein essentially comprises a;hydr ocarbon oxidizer ill-,ametal oxide regeneratorfii) and-a clean-up oxidizer 50 whose functions and cooperation will be explained forthwith using the conversion .of natural gas with titanium o i e- KR ZQmQ-H Q comp si e .ipeh b t.. -Fe s- 'N Q-and 10% CraOs) in the first stage andoxygen of %purity in the secondas an example..- It should be understood, however, that other hydrocarbon gases and other metal oxides may be used in a substantially analogous manner. I i v In operation, hydrocarbon oxidizer l0 contains adensebed. i2 of titanium dioxide having a .'par-. ticle size of about 200-300 meshfiuidiz ed to form an upper-level L10 at about 5-1'5"f t. e1evation,,by the gaseous reactants and reaction products nowing upwardly at a superficial linear velocity of about lj ft. per secondatthe top of the bed. Natural gas, preferably preheated to atemperature of sm t w-1 cmi utplies ro h .111511% an -st m r eat d i r em perature-rnay beadded through line I am fluid; izetionen .canrers n psrpqses- Pr n i i l d-T ips-pi h; e ieeql isee empl sh d j i e ie tione dist t n me n 3 ja' Pe o sri r h ,t;. 1:; U r h I Metal oxide regenerator 30 is arranged an e1eva d Q iti9 w t 79251 6 o.- x r n cents den e be 32 1? d 9 e xi nth 9f eo idet ean k ili e .id

m s fiw lleorby-air, Preferably lprehe'ated to and r t a;su e fici lli ie xr l ei r wi eeene aprifl 1# t. s d e n we-an s. suffieient t r i z m a a l w r metal oxides to the higher'oxidation stagedesired for oxidizer-3 1 fla hbout 2- 3 j'voluines" of, air per volume ofnatural gas charged is usually adequate.

for -this purpose. O xid iz er in may be maintained at an elevatedpressurepi, sa aboiitflS-ZOO lbs,

per sguare inch-preferably -150 lbs. per square inch while regenerator -30 is kept at a lower pressure, preferablyv a t about atmospheric; to lbs. per squareinch.

; ,R'eoxidized titaniurndioxide is .withdrawnfrom a lower portion of bed 32 into a standpipepi fis aera e ;ltnro ghq aps a flows zlllld f t ps udo-hyd atic-: ss 9f; l-f en ev phase 32 and. standpipeg36provided with abot'tom control valve: :39 ,substantially at the-teinperature of .bed

32, iintooxidizer. l0, isreducedtherein. by the natural gas and -treturned through the reverse standpi' eidtl provided with a top control valve 44 V anger h pressure-of oxidizer 'lll tojregenerator 301*- Control valve 44 iiiay also be placed lower ihrEVerse Rs'taY-idDipeim m wmehaae terationduring the starting period.

one heat required Io'rthe oxidation M net-oralgas in *O'Xifliz'r It is suppliedas sensibleheat "crr'e'oxid ized metal oxide sup'pli'e'd fromregenerator 3'0 throu'gh standpipe 36. T acoomplishwliis, regenerator 30 operated at a temperature higher than that of oxidizer 10,- isay 'hi'gher by automate -200 F or mo're. tiperating tempera tu-res forti'tani" 'fiidxidemay be about 1500"- 1 900'- it, preferably about 1600" 'm reg'enerator so air'd about 140N460? preferably about 1500' in oxidizer 1 0-. At these conditions; a solids=tii'rcl'llatioiirate of about *8 to 12 lbs. per cubic ft. or riat urargas to be 'scnvertearis general'ly-s'ufmc'ient to maintain the desi redbalance. r r

Residual air containing about95=-l00% nitrogen is withdrawn from-level Lao through a gas solids separator; such a's cyclone 33 p (fed with solids return pipe 31 and'then thro ghline' 43', tobe usedfor any 'desir'ed purpose,- preferably after heat-exchange with process gases andfo'r' solids; If desired, tre'sh metal or "metaloxide may be supplied to reoxidizer through line 35 and meta-1 oxide fines-of undesirably small size may be discarded through line 46.

Returning now-to oxidizer In, a partially converted product gas which may 'still'c'ontai-n up to about 10% or more of unconverted methane is withdrawn irom level L10 and passed substantially at the temperature and-pressureof oxidizer I0 through line 48 to clean-up oxidizer 50. Oxygen of about'-95% purity, Preferably preheatedio about 7.00 -900 F., is suppliedthrough line 52:17.0 clean-up oxidizer 50 in amounts suflicient toyrconvert the remainder of thenaturalxgas to GO and m ahdyto maintain a temperatureiofabout 2100":- 2300." F. within oxidizerjfl-i- About 2-41-volumes of oxygen per 100 volumes of gas supplied through line 48 is usuallysufiicient for this purpose. Any metal or metal oxide fines carried from oxidizer l0 to oxidizer 50 by the gas passing through line 48 are sintered and agglomerated in oxidizer 50 so that the large particles formed will drop out of the gas and collect in the bottom of oxidizer 50 from which they may be removed continuously or periodically through line 53, to be returned through line 35 to regenerator 30, preferably after grinding to the desired particle size.

Product gas consisting predominantly of CO and H2 and containing mere traces of unconverted hydrocarbon and relatively small amounts of CO2 and H20 is withdrawn from oxidizer 50 through line 54. Its heat content may be used to preheat process gases and/or solids in any conventional manner. It may be used directly for the catalytic synthesis of hydrocarbons, if desired, after purification. The product gas may also be reacted wholly or in part with steam to convert CO to CO2 which may be removed to produce pure hydrogen.

The embodiment of the invention illustrated by the drawing permits of various modifications. Purging stages may be provided in lines 36 and 40 using inert gases such as steam, residual air, etc. in a manner known per se., to prevent the formation of explosive mixtures. A gas solids separator similar to separator 33 may be arranged between oxidizer l0 and line 48. The gas leaving regenerator 30 may be cooled prior to its entry into separator 33 to prevent damage thereto by overheating. Separator 33 may then v Natural gas preheating temperature, "itv oxygen feed rate 'to' be arranged outslde regenerator insteeaiot. usingestandpipes zit-and 4'0 fcr :circulatingrsclidsbetween oxidizer I'll and regenerator tmi'rdther conventional meansiron-conveying*rluidizedzsolids may be used, such as mec'hani'cal conveyors, lock hoppers, "etc.

The invention "will following specific 'example.

mi f below: v

Natural gas reed rate -(0% il'lOIS/hl.

Steam feed rate'tooxidi'zer H1, mole/hr"- Steam preheating temperature, ,-F

Air feed rate to'regenerator 30'. mols/hr 30900 Air preheating temperature, 'F i "oxidizer on, mols/hr. Preheating temperature of "oxygen,,"F; Temperaturein oxidizer in, F. v Pressure in oxidizer 'lng lbs'7'sq," in; au e o Temperature in regenerator 30, F' Pressure in regenerator 3'0, ibs/sq. in."

gauge Temperature in "oxidizer 50, F 20 Pressure in "oxidizer 5'0, lbsjsq. iii, 7 gauge s i; 44m h;;, Solids circulation rate, based on "T102 "'be twe'en oxidizer 1' 0 andregenerator 30" tons/min. ..h; l;l; Nitrogen product on in regenerator "to, mOIS/hr; ,g l. .;.i.i; I Total gas production in oxidizer i0,

mols/hr. 39,900 Production of CO+H2 in oxidizer l0,

mols/hr. 27,700 Composition of gas produced in oxidizer CO percent 19.6 49.9 6.4 2.0 15.9 5.8 0,4

While the foregoing description and exemplary operations have served to illustrate specific applications and results of my invention, other modifications obvious to those skilled in the art are within the scope of my invention. VOnly mismana ed a the r 7 suchlilimitatioiis ishould 1:.1 An improved process for lmanufaoturing-z a gaseous .iuel; containing. predominantly H2 and 00, which comprises continuously forcing a hy-:'

drocarbon; zgas. predominantly. .methane into. a

conversion zone containing .a. fluidized mass .of a

finely-divided metal oxide adapted to convert said hydrocarbon gas to hydrogen and CO, maintaining:'- a temperature within said conversion zone within the range of from about 1400" -to 1600 permitting contact betweengsaid gaseoushydrocarbon and saidfluidized metal oxidefor a suf ficient period of time to permitat leastepartialconversion of said hydrocarbon gas into Hz a'nd CO, withdrawing a produce containing said H2 and CO and hydrocarbon 'unreacted gas, and also entrained 'metai contamingifines, frorn said con version z'one charging said gas to a second zone contacting said gas with'substaiitially pure oxy;

gen in said secondfzone. suflicient in amountsub be imposed on,the' -in;-1,Z ven'tiongaszarezindicated imthe appended claims;

stantially completelyto convert said unreac'ted hydrocarbon" gas iritoj H2 and CO, and I to sinter and agglomerate metal-containing particles, by n sai la t nameazonefatemo ture ,within" "the range of frorn about 20001 to 2'5 0'0" F; and withdrawing 'frornfljsaid second zone a produc't gas substantially free of hydrocar bons and also recovering from 'said'second zone the sintered and a lom i f ifi'e'dimetal-containing rfinea Q2, Animproved process for manufacturing agais'e'ous fuel containing predominantly H2 CQ, which comprises continuously forcing ahiydrocarbonga's into a conversion "zone; .ocntaining a fluidized massof a finely divided 'rnetaloxide adaptedto convert said hydrocarbon gasto hydr'ogen and maintaining atrriperature. with insaid conversio'ii'zone within the range or f'rom about 1400 1 1 00 F}. permitting contact p tween saidas ous. hydroearb ri' and-said; fluid d.

metalox-ide. for a.sufiicient period of time-toper- Init at leastpartia-l conversion of. said hydrocarbon gas into H2 and C0,pwithdrawing aproduct 7 containing said Hzand COandhydrocarbon unreactedigas, and also;v entrained metal-containing fines qfrom :said conversion. j zone, charging; said gasgtq asecond; zone, contacting, said gas with,

substantially pure oxygen in said second zone suflicientflin amount substantially completely to convert qsaidunreacted: hydrocarbon gas into H2 andjCQ-and to sinter and agglomerate metal-- containing particles, by maintaining in said last named zone a temperature within the range of. irqmlabout 2000*. .to 2500?..F-.,ia r win from said second-zone a product gas substantially freeof hydrocarbons; and also recovering from saidzsecond zone the sintered and agglomerated metal-containing fines. 7 r 3. The process1of5o1airn, 2in which reduced metal oxideis; withdrawn from said conversion zone, regenerated with; air in. the form of? dense,; turbulent, fluidized mass of solids in o a regeneration. zone .at; arioxidizing; temperature and returned to said' conversion. zone substan tially at the temperature of said regeneration zone.

M 7 aefeeee ijoes c'r'run ...The following.referencesarebf record, in thefile ofzthis patentz a, v

I UNITE s ATEs eA EnTs Number Date Dec. 13, 1949 LL-WARYILVENYK. LEWlS, JR. 

1. AN IMPROVED PROCESS FOR MANUFACTURING A GASEOUS FUEL CONTAINING PREDOMINANTLY H2 AND CO, WHICH COMPRISES CONTINUOUSLY FORCING A HYDROCARBON GAS PREDOMINANTLY METHANE INTO A CONVERSION ZONE CONTAINING A FLUIDIZED MASS OF A FINELY-DIVIDED METAL OXIDE ADAPTED TO CONVERT SAID HYDROCARBON GAS TO HYDROGEN AND CO, MAINTAINING A TEMPERATURE WITHIN SAID CONVERSION ZONE WITHIN THE RANGE OF FROM ABOUT 1400* TO 1600* F., PERMITTING CONTACT BETWEEN SAID GASEOUS HYDROCARBON AND SAID FLUIDIZED METAL OXIDE FOR A SUFFICIENT PERIOD OF TIME TO PERMIT AT LEAST PARTIAL CONVERSION OF SAID HYDROCARBON GAS INTO H2 AND CO, WITHDRAWING A PRODUCE CONTAINING SAID H2 AND CO AND HYDROCARBON UNREACTED GAS, AND ALSO ENTRAINED METAL-CONTAINING FINES, FROM SAID CONVERSION ZONE, CHARGING SAID GAS TO A SECOND ZONE, CONTACTING SAID GAS WITH SUBSTANTIALLY PURE OXYGEN IN SAID SECOND ZONE SUFFICIENT IN AMOUNT SUBSTANTIALLY COMPLETELY TO CONVERT SAID UNREACTED HYDROCARBON GAS INTO H2 AND CO, AND TO SINTER AND AGGLOMERATE METAL-CONTAINING PARTICLES, BY MAINTAINING IN SAID LAST NAMED ZONE A TEMPERATURE WITHIN THE RANGE OF FROM ABOUT 2000* TO 2500* F., AND WITHDRAWING FROM SAID SECOND ZONE A PRODUCT GAS SUBSTANTIALLY FREE OF HYDROCARBONS AND ALSO RECOVERING FROM SAID SECOND ZONE THE SINTERED AND AGGLOMERATED METAL-CONTAINING FINES. 